Heart disease, also called “cardiovascular disease,” is a broad term used to describe a range of diseases that affect the heart and/or blood vessels. The conditions include coronary artery disease, heart attack, high blood pressure, stroke and heart failure. Cardiovascular disease is the No. 1 worldwide killer of men and women; e.g., in the U.S. it is responsible for 40 percent of all deaths, more than all forms of cancer combined.
A common form of cardiovascular disease is coronary artery disease, which affects the arteries that supply the heart muscle with blood. Sometimes known as “CAD,” coronary artery disease is the leading cause of heart attacks. It generally means that blood flow through the coronary arteries has become obstructed, reducing blood flow to the heart muscle. The most common cause of such obstructions is a condition called atherosclerosis, a largely preventable type of vascular disease. Coronary artery disease and the resulting reduced blood flow to the heart muscle can lead to other heart problems, such as chest pain (angina) and heart attack (myocardial infarction).
A heart attack is an injury to the heart muscle caused by a loss of blood supply. The medical term for heart attack is “myocardial infarction,” often abbreviated MI. A heart attack usually occurs when a blood clot blocks the flow of blood through a coronary artery—a blood vessel that feeds blood to a part of the heart muscle. Interrupted blood flow to a heart can damage or destroy a part of the heart muscle.
A heart disease that affects the heart muscle itself is called a “cardiomyopathy.” Some types of cardiomyopathy are genetic, while others occur for reasons that are less well understood. Types of cardiomyopathy include ischemic, which is caused by loss of heart muscle from reduced coronary blood flow; dilated, which means the heart chambers are enlarged; hypertrophic, which means the heart muscle is thickened; and idiopathic, which means the cause is unknown. One of the most common types of cardiomyopathy is idiopathic dilated cardiomyopathy—an enlarged heart without a known cause.
Heart disease can be either acquired (later in life) or congenital. Congenital heart disease refers to a form of heart disease that develops before birth (congenital). Congenital heart disease is a broad term and includes a wide range of diseases and conditions. These diseases can affect the formation of the heart muscle or its chambers or valves. They include such conditions as narrowing of a section of the aorta (coarctation) or holes in the heart (atrial or ventricular septal defect). Some congenital heart defects may be apparent at birth, while others may not be detected until later in life.
Next to the heart muscle itself, heart disease can also affect other structure, such as the heart valves. Four valves within the heart keep blood flowing in the right direction. Valves may be damaged by a variety of conditions leading to narrowing (stenosis), leaking (regurgitation or insufficiency) or improper closing (prolapse). Valvular disease may either be congenital, or the valves may be damaged by such conditions as rheumatic fever, infections (infectious endocarditis), connective tissue disorders, and certain medications or radiation treatments for cancer.
Heart rhythm problems (arrhythmias) occur when the electrical impulses in a heart that coordinate heartbeats do not function properly, causing the heart to beat too fast, too slow or irregularly. Other forms of cardiovascular disease can indirectly cause arrhythmias.
Perhaps the most common form of cardiovascular disease in the Western world, affecting about one in four Americans, is high blood pressure (hypertension), which means that the blood is pumped with excessive force through the blood vessels. Although potentially life threatening, it is one of the most preventable and treatable types of cardiovascular disease. High blood pressure also causes many other types of cardiovascular disease, such as stroke and heart failure.
Heart failure, a progressive disorder in which damage to the heart causes weakening of the cardiovascular system, can result from any of the before-mentioned structural or functional cardiac disorders. It manifests by fluid congestion or inadequate blood flow to tissues as a result of the heart's inability to fill with or pump a sufficient amount of blood through the body.
Depending on the side of the heart affected, the symptoms can be diverse and diagnosis is impossible on symptoms alone. Left-sided heart failure results in congestion of the lung veins and symptoms that reflect this, as well as poor circulation to the body, whereas right-sided heart failure presents with, e.g., peripheral edema and nocturia.
Heart failure may result from one or the sum of many causes. Many affect both sides, such as ischemic heart disease, chronic arrhythmias, cardiomyopathy, cardiac fibrosis, chronic severe anemia, and thyroid disease, whereas others, such as hypertension, aortic and mitral valve disease and coarctation, mainly cause left-sided heart failure and pulmonary hypertension and pulmonary or tricuspid valve disease often result in right-sided heart failure.
These causes of heart failure have in common that they all reduce the efficiency of the myocardium, or heart muscle, through damage or overloading. Over time, the resulting increase in workload will produce changes to the heart itself, which, for instance, include reduced contractility, a reduced stroke volume, reduced spare capacity, increased heart rate, hypertrophy of the myocardium and/or enlargement of the ventricles. These changes of the heart result in reduced cardiac output and increased strain on the heart, which increases the risk of cardiac arrest and reduces blood supply to the rest of the body.
Current treatment of heart failure focuses on treating the symptoms and signs and preventing the progression of the disease. Treatment includes exercise, eating healthy foods, reduction in salty foods, and abstinence from smoking and drinking alcohol. Further, pharmacological management can be applied focused on relieving symptoms, maintaining a euvolemic state, and delaying progression of heart failure. Drugs used include: diuretic agents, vasodilator agents, positive inotropes, ACE inhibitors, beta blockers, and aldosterone antagonists.
Heart failure is a serious disorder that carries a reduced life expectancy. Many forms of heart failure can be controlled with medication, lifestyle change, and correction of any underlying disorder. However, heart failure is usually a chronic illness, and it may worsen with infection or other physical stressors. There is no real cure for heart failure.
Therefore, there is an unmet need for alternative treatments for heart failure and heart disease in general.